Commercial cattle breeding constantly strives for ways to increase the efficiency of its operations. One relevant issue for this sector is the frequency with which multiple calves are born in one event (known as the “twinning” rate), which is of concern to both dairy and beef cattle breeding. Twinning, albeit, a relatively low frequency event, is disadvantageous in the production of dairy cattle, since cows having multiple births generally produce lower quantities of milk, and for shorter periods of time than cows having single births. On the other hand, multiple births in beef cattle can be desirable due to the additional calves per birth. Twinning has a heritable, multigenic basis, but the specific genes underlying twinning have not yet been identified. Thus, there is an ongoing need to understand and exploit the genetic basis of twinning for selective cattle breeding so as to decrease or increase twinning rates depending on the particular cattle breeding sector, e.g., dairy cattle or beef cattle.